Prostatic- Minimal invasive approach: pros and pitfalls

Prostatic neoplasia occurs uncommonly in the dog (representing <0,6 of all reported canine tumors). Several studies have documented an increased prevalence in neutered male suggesting a hormonally independent neoplasia and that castration may favour the development and progression of prostatic neoplasia although this remains somewhat controversial. The urothelial cell carcinoma (previously referred to as a transitional cell carcinoma) and adenocarcinoma are the most common  prostatic neoplasia reported in dogs.

The metastatic potential of prostatic tumors is high (>60% consistently reported) with spread to the regional lymph nodes, lumbar vertebrae, lungs and other long bones being reported. The use of high definition computer tomography (CT) has increased the detection of early metastatic disease however the majority of patients are still euthanized due to the local effects of the primary neoplasia (dysuria, stranguria, tenesmus). Clinical signs relating to metastatic disease (lameness and pain) are rarely present at diagnosis but the potential role for metastatic spread to impact on the patients quality of life should be considered in all cases prior to undertaking any intervention.

The role of systemic chemotherapy in prostatic neoplasia has previously been questioned however a 2018 study (Ravicini et al) documented a statistically significant improved median survival time in those patients receiving intravenous chemotherapy and non steroidal anti-inflammatory drugs vs. non steroidal anti-inflammatory drugs alone (MST 106 days vs. 51 days; range 9-752 days). The presence of metastatic disease and being an entire male dog were identified as negative prognostic factors. This study did not differentiate all tumours histologically into urothelial cell carcinoma vs. adenocarcinoma. The overall limited response however to intravenous chemotherapy has lead to an increasing interest in more targeted options for treating this disease.

Radiotherapy options such as stereotactic radiosurgery and IM/IGRT (intensity-modulated and image-guided radiation therapy) are provided at a limited number of centres in the world. The average survival time reported in patients receiving systemic chemotherapy, non-steroidal anti-inflammatory medication and IM/IGRT is 20 months. [...]